Relaxation mechanism and conductivity studies of lead-free ceramics: Fe1/2(NaLi)1/4TiO3

2020 ◽  
Vol 34 (06) ◽  
pp. 2050081
Author(s):  
Subrat Kumar Barik ◽  
A. R. Atique Ulla
Keyword(s):  
Complex Impedance ◽  
Negative Temperature ◽  
Relaxation Mechanism ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Prepared Sample ◽  
Lead Free Ceramics ◽  
Wide Range ◽  
Different Temperatures ◽  
Energy Formula

A single-phase lead-free ferroelectric compound, Fe[Formula: see text](NaLi)[Formula: see text]TiO3, is found at room temperature. The solid state reaction technique helps to process the sample at the calcination and sintering temperatures of 900 and 950[Formula: see text][Formula: see text]C for 4 h respectively. The desired phase and crystal structure formation of the prepared sample are confirmed by analysis of X-ray diffraction (XRD) data and are found to be in orthorhombic structure. The correlation among phase formation and physical properties has been established by using complex impedance spectroscopy (CIS) method over a wide range of frequencies (from 100 Hz to 1 MHz) and different temperatures (25–280[Formula: see text][Formula: see text]C). The overlap depressed semicircular arcs represent the association of grain and grain boundary effects in the material. Activation energy [Formula: see text] is noted to be 1 eV for the prepared sample. The frequency dependent ac conductivity is followed by Jonscher’s universal power law. DC conductivity versus temperature graph also indicates the negative temperature coefficient of resistance (NTCR) behavior of the material.

scholarly journals Dielectric, ferroelectrics properties and impedance spectroscopy analysis of the [(Na0.535K0.480)0.966Li0.058](Nb0.90Ta0.10)O3-based lead-free ceramics

2015 ◽  
Vol 05 (01) ◽  
pp. 1550007 ◽  
Author(s):  
M. Saidi ◽  
A. Chaouchi ◽  
S. D'Astorg ◽  
M. Rguiti ◽  
C. Courtois
Keyword(s):  
Complex Impedance ◽  
Negative Temperature ◽  
Impedance Analysis ◽  
Xrd Analysis ◽  
Ac Impedance ◽  
Nyquist Plot ◽  
X Ray Diffraction ◽  
Complex Impedance Analysis ◽  
Lead Free Ceramics ◽  
Different Temperatures

Polycrystalline of [( Na 0.535 K 0.480)0.966 Li 0.058] (Nb 0.90 Ta 0.10) O 3 samples were prepared using the high-temperature solid-state reaction technique. X-ray diffraction (XRD) analysis indicates the formation of a single-phase with orthorhombic structure. AC impedance plots were used as tool to analyze the electrical behavior of the sample as a function of frequency at different temperatures. The AC impedance studies revealed the presence of grain effect, from 425°C onwards. Complex impedance analysis indicated non-Debye type dielectric relaxation. The Nyquist plot showed the negative temperature coefficient of resistance (NTCR) characteristic of NKLNT. The AC conductivity results were used to correlate with the barrier hopping (CBH) model to evaluate the binding energy (Wm), the minimum hopping distance (R min ), the density of states at Fermi level (N(Ef)), and the activation energy of the compound.

COMPLEX IMPEDANCE SPECTROSCOPY ON ZnO-B2O3 DOPED (Ba, Sr)TiO3 CERAMICS

2010 ◽  
Vol 17 (01) ◽  
pp. 27-32 ◽  
Author(s):  
SANG-HO MOON ◽  
YONG-SU HAM ◽  
JUNG-HYUK KOH
Keyword(s):  
Impedance Spectroscopy ◽  
Complex Impedance ◽  
Negative Temperature ◽  
Nyquist Plot ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Bst Ceramics ◽  
Grain Growth Behavior ◽  
Microscopy Images

BST ceramics with doping of 1, 3, and 5 wt.% ZnBO were prepared by the conventional mixed oxide method and sintered at 1100°. X-ray diffraction analyses were carried out to verify the structural properties. 1, 3, and 5 wt.% ZnBO doped BST ceramics were crystallized with weak tetragonal structure at 1100°C. The grain growth behavior and shapes were investigated by scanning electron microscopy images. The electrical properties of 1, 3, and 5 wt.% ZnBO doped BST ceramics were investigated by impedance spectroscopy at the different temperatures (350, 375, and 400°C). Impedance spectroscopy data presented in Nyquist plot show the existence of both grain and grain boundary effects in all specimens. 1, 3, and 5 wt.% ZnBO doped BST ceramics showed negative temperature coefficient of resistance (NTCR). Also, the capacitances and resistances of grains and grain boundaries for 1, 3, and 5 wt.% doped BST ceramics were simulated through equivalent circuit with the parallelly connected capacitors and resistors. The capacitance and resistance were decreased when temperature and ZnBO dopants were increased.

scholarly journals Evaluation of structure, dielectric and electrical properties of (Li/Ta/Sb) modified (Na, K) NbO3 lead-free ceramics with excess Na concentration

2017 ◽  
Vol 07 (06) ◽  
pp. 1750037 ◽  
Author(s):  
Md. Kashif Shamim ◽  
Arpana Singh ◽  
Seema Sharma
Keyword(s):  
Single Phase ◽  
Ferroelectric Properties ◽  
Structural Phase ◽  
Complex Impedance ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Lead Free Ceramics ◽  
Raman Modes

Polycrystalline perovskite structured (Li[Formula: see text] (Na[Formula: see text] K[Formula: see text])[Formula: see text] (Nb[Formula: see text]Ta[Formula: see text] Sb[Formula: see text] O3 ceramics with [Formula: see text], 0.005 and 0.01 mole excess Na concentration were prepared by solid state sintering method. The present study relates the role of excess Na addition with the stoichiometry, density, structure, dielectric and ferroelectric properties of the samples. X-ray diffraction (XRD) pattern exhibits single phase orthorhombic structure. The characteristic Raman modes were observed due to translational modes of cations and vibrational modes of NbO6 octahedra and no structural phase transition were observed. This confirms the formation of single phase perovskite structure and is consistent with XRD results. The dielectric permittivity increases about two times, while dielectric loss decreases by four times for [Formula: see text] composition. The electrical measurements carried by Complex Impedance spectroscopic analysis suggest negative temperature coefficient of resistance (NTCR) behavior.

scholarly journals Dielectric response and pyroelectric properties of lead-free ferroelectric Ba3(VO4)2

2015 ◽  
Vol 05 (01) ◽  
pp. 1550006 ◽  
Author(s):  
Biswajit Pati ◽  
R. N. P. Choudhary ◽  
Piyush R. Das ◽  
B. C. Sutar
Keyword(s):  
Dielectric Response ◽  
Negative Temperature ◽  
Pyroelectric Coefficient ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Dielectric Parameters ◽  
Wide Range ◽  
Phase Compound ◽  
Sem Micrograph ◽  
Tan Δ

The current paper presents results of dielectric response, pyroelectric behavior and conductivity study of lead-free ferroelectric barium orthovanadate ( Ba 3( VO 4)2 or Ba 3 V 2 O 8) ceramic, for a wide range of temperature and frequency. An X-ray diffraction study suggests the formation of a single-phase compound in trigonal crystal system. The SEM micrograph of gold-coated pellet sample shows well-defined and homogeneous morphology. Detailed studies of dielectric parameters (εr and tan δ) of the compound as a function of temperature and frequency reveal their independence over a wide range of temperature and frequency. The nature of Polarization versus electric field (P–E) hysteresis loop of Ba 3 V 2 O 8 at room temperature suggests its ferroelectric nature. The temperature dependence of pyroelectric coefficient and figure of merits of the sample support its dielectric response. The nature of variation of dc conductivity with temperature confirms the Arrhenius and negative temperature coefficient of resistance (NTCR) behavior of the material.

Dielectric Behavior of Mechano-chemically Synthesized [(CH3NH3)3Bi2Br9]: A Lead Free Hybrid Perovskite

2021 ◽  
Author(s):  
Swagatalaxmi Pujaru ◽  
Priyabrata Sadhukhan ◽  
Basudev Ghosh ◽  
Arup Dhara ◽  
Sachindranath Das
Keyword(s):  
Impedance Spectroscopy ◽  
Complex Impedance ◽  
Negative Temperature ◽  
Dielectric Behavior ◽  
Lead Free ◽  
Published Data ◽  
Temperature Dependent ◽  
Microstructural Parameters ◽  
Hybrid Perovskite ◽  
Refinement Method

Abstract Lead free hybrid halide perovskite (CH3NH3)3Bi2Br9 has been successfully synthesized by mechano-chemical method. The microstructure analysis by Rietveld’s refinement method revealed that the crystal belongs to trigonal system with space group P3 ̅m1. The obtained microstructural parameters are well in agreement with the previously published data. Temperature-dependent ac conductivity, impedance spectroscopy, and complex dielectric properties have been investigated in detail. The negative temperature coefficient of resistance behaviour reveals the semiconducting nature of the materials. The complex impedance spectroscopy also supports the semiconducting nature of the sample with activation energy for conduction ~0.38 eV.

Structural, dielectric, electrical and piezoelectric properties of Ba4SrRTi3V7O30 (R=Sm, Dy) ceramics

Open Physics ◽  
2008 ◽  
Vol 6 (4) ◽  
Author(s):  
Priyadarshini Sahoo ◽  
Anuradha Panigrahi ◽  
Sunanda Patri ◽  
Ram Choudhary
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Complex Impedance ◽  
Tungsten Bronze ◽  
Negative Temperature ◽  
Scanning Electron Micrographs ◽  
Polarization Study ◽  
Semiconducting Properties ◽  
Wide Range

AbstractPolycrystalline samples of Ba4SrRTi3V7O30 (R=Sm and Dy), members of the tungsten-bronze family, were prepared using a high-temperature, solid-state reaction technique and studied their electrical properties (using complex impedance spectroscopy) in a wide range of temperature (31–500°C) and frequency (1 kHz-1 MHz). Preliminary structural (XRD) analyses of these compounds show the formation of single-phase, orthorhombic structures at room temperature. The scanning electron micrographs (SEM) provided information on the quality of the samples and uniform distribution of grains over the entire surface of the samples. Detailed studies of the dielectric properties suggest that they have undergone ferroelectric-paraelectric phase transition well above the room temperatures (i.e., 432 and 355°C for R= Sm and Dy, respectively, at frequency 100 kHz). Measurements of electrical conductivity (ac and dc) as a function of temperature suggest that the compounds have semiconducting properties much above the room temperature, with negative temperature coefficient of resistance (NTCR) behavior. The existence of ferroelectricity in these compounds was confirmed from a polarization study.

Piezoelectric properties of lead-free (Na0.5Bi0.5)TiO3–(Na0.5K0.5)NbO3–BaTiO3 ceramics

2008 ◽  
Vol 23 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Seung-Ho Lee ◽  
Chang-Bun Yoon ◽  
Sung-Mi Lee ◽  
Hyoun-Ee Kim ◽  
Kyung-Woo Lee
Keyword(s):  
Crystal Structure ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Microstructural Evolution ◽  
Piezoelectric Properties ◽  
Lead Free ◽  
Cubic Phase ◽  
Lead Free Ceramics ◽  
Wide Range

The microstructural evolution and piezoelectric properties of lead-free ceramics (0.98-x)(Na0.5Bi0.5)TiO3–x(Na0.5K0.5)NbO3–0.02BaTiO3 (0 ⩽ x ⩽ 0.98, abbreviated as (0.98-x)NBT–xNKN–0.02BT) were investigated. The effects of the amount of NKN on the crystal structure, microstructural evolution, and piezoelectric properties were examined. The 0.93NBT–0.05NKN–0.02BT ceramics having a lower NKN content gave good performances with piezoelectric properties of d33 = 140 pC/N and kp = 21%, because of the soft additive Nb5+ ions at the B sites. However, a paraelectric cubic phase was observed in the wide range of compositions between x = 0.1 and x = 0.9. At a higher NKN content of x > 0.9, a morphotropic phase boundary (MPB) between the tetragonal and orthorhombic phases was found in the 0.015NBT–0.965NKN–0.02BT ceramics, and the piezoelectric properties were enhanced (d33 = 135 pC/N, kp = 29%). The piezoelectric properties of this system were closely related to its crystal structure.

scholarly journals Structural, Dielectric, Magnetic and Magneto-Dielectric Properties of (1-x)BiFeO3–(x)CaTiO3 Composites

2021 ◽  
Author(s):  
Bushra Khan ◽  
Aditya Kumar ◽  
Preeti Yadav ◽  
Gulab Singh ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Ac Conductivity ◽  
Sol Gel ◽  
Negative Temperature ◽  
Tangent Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Changes ◽  
Different Temperatures ◽  
Ferromagnetic Ordering ◽  
Jonscher’S Power Law

Abstract (1-x) BiFeO3–(x) CaTiO3 [(1-x) BFO – (x) CTO, (x = 0, 0.1, 0.2 and 0.3)] composites were synthesized using sol-gel chemical rout method. X-ray diffraction investigation shows the crystal structure changes from rhombohedral to monoclinic for 0 ≤ x ≤ 0.2, and it changes to orthorhombic at x ≤ 0.3. The Field Emission Scanning Electron Microscope (FESEM) investigation confirms the the microstructure consists of randomly oriented, homogenous, and non-uniform grains. The dielectric permittivity (ε) and tangent loss (tanδ) decreases with increasing frequency and show dielectric anomalies (as a hump) at different temperatures for different compositions. The incorporation of CTO, decreases three order of leakage current (up to x = 0.2) and significantly improve the magnetization and magneto-dielectric coupling. The frequency-dependent ac conductivity obeys Jonscher’s power law with large ac conductivity dispersion for higher frequencies with increasing CTO concentration. The variations of ac conductivity with the inverse of temperature obey the Arrhenius equation and show negative temperature coefficient of resistance (NTCR) behavior. The ferromagnetic (FM) properties in BFO-CTO increases significantly with an increase of the CTO concentration. The coercive field increases with increasing CTO concentration suggesting a competition between the antiferromagnetic and ferromagnetic ordering. At room temperature, all the samples show strong magneto-dielectric coupling.

scholarly journals Structural, microstructural and dielectric characterizations of (Bi0.5Na0.5)TiO3based lead-free ferroelectric ceramics

2021 ◽  
pp. 2140006
Author(s):  
B. R. Moya ◽  
A. C. Silva ◽  
A. Peláiz-Barranco ◽  
J. D. S. Guerra
Keyword(s):  
Lead Free ◽  
Ferroelectric Ceramics ◽  
Reaction Sintering ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Porosity Level ◽  
X Ray ◽  
Ceramic Samples ◽  
Lead Free Ceramics ◽  
Sintering Method

(1–[Formula: see text]Bi[Formula: see text]Na[Formula: see text]TiO3–[Formula: see text]BaTiO3 lead-free ceramics have been obtained from the conventional solid-state reaction sintering method. The structural properties were investigated from X-ray diffraction and Raman spectroscopy techniques. Results revealed well-crystallized ceramic samples with perovskite structure. Microstructural properties, obtained from scanning electron microscopy measurements, have shown high density with very low porosity level. The dielectric response, analyzed as a function of the temperature and several frequencies, showed very broad peaks with a strong frequency dependence of the temperature for the maximum dielectric permittivity for the modified system. Results were analyzed considering the influence of the BaTiO3 content on the studied physical properties.

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